Decitabine improved the number and function of MDSCs. (A) Representative scattergram of PBMCs and CD11b⁺CD33⁺ cells within the PBMC gate. Histograms of CD11b⁺CD33⁺HLA-DR^low cells from healthy controls and ITP patients. (B) The proportion of CD11b⁺CD33⁺HLA-DR^low cells in PBMCs was lower in ITP patients than in healthy controls (unpaired Student t tests, ∗∗∗P = .0002) and (C) increased after decitabine treatment (paired Student t tests, ∗∗P = .0015). Histograms of (D) Arg1and (G) iNOS in CD11b⁺CD33⁺HLA-DR^low cells from healthy controls and ITP patients before treatment. (E-F) The expression (mean fluorescence intensity) of Arg1 in circulating MDSCs was lower (unpaired Student t tests, ∗∗P = .0032) in ITP patients than in healthy controls and was higher after decitabine treatment (paired Student t tests, ∗∗P = .0035). (H-I) The expression (mean fluorescence intensity) of iNOS in circulating MDSCs was higher (unpaired Student t tests, ∗P = .0182) in ITP patients than in healthy controls and was lower after decitabine treatment (paired Student t tests, ∗∗P = .0011). Bars represent mean ± standard deviation.